Reinforced-concrete slab.



R; A. CUMMINGS.

REINFORGED GONGRETE SLAB. APPLIOATION I'ILED JUNE 11, 1909.

1,@35323. ;mema Aug. 13,1912.

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' To aZZ 'whom it may concem:

'adjoining panele over the beamsor. other UNITED 'STATES PATENT OFFICE.

ROBERT A. CUMMINGS, or BEAVER, EENNSYLVANIA.

REINFORCED-CONCRETI; SLAB.

1935323. Specification of Letters Patent. Patentd Aug 13, 3912,

Application filed .Tune 11 1909. Serial No. 501530.

structure, and which will equaliy take care of either tension or compression stresses in both sides of the slab or like structure.

In the accompanying drawings Figure 'l is a vertical sectionthrough a slab having therein' the simplest form of my reintorce- 'ment; Fg. 2 is u similar view illustrating a modification', Fig. 3 is a similar view showing the Construction of Fig. 1 with the uddition of straight trainsverse members at the bott 'zni; Fig. 4 is a simil r View showing my reinorcement in a more complete. form; Fig. 5 is &plan view of the reinforce ment shown in Fig. 4; Fig. 6 is a vertical section showing another modification; and Figs. 7, 8 and 9 are detail views of portions of the structure.

-In the drawings the numeral 1 indicates the body of the concrete slab, which may be a floor, ceiling, root or other portion of a building, viaduct, vault or the like. The reintorcement in its simplest form, shown in Fig. l, embodies a series ot main reinforcement members or rods 2 which ere lo cated in the lower portion of 'the s lab, rier its lower surface, :and which for brevity 'of description :tre termedlongitudinal tension members, although as a matter of fact the slab may be shorter in ,the direction. in which these members extend than in the direction 'at right angles thei-eto. Connect ing these mitin or longitudi'nal members 2 are a series of secondary members 3 'which ,1 will term transverse members, which between the members 2 are bent upwardly as shown to form zig'zg strips and loops 4 extending up into proximity to the top surface of the 'sleb, and which become'embedded in the concrete' and tie the tension members 2 to a body of concrete which is in compression The Zig Zag members 3 may he in planes at right angles tothe planes of the main tension members or at an angle thereto. This form of reiuforcement is particularly adapted to such slabs as ere supported st their edges, and in which the lower surtaces are in tension. The rods 2 in this case take care of the tension stresses while the loops i extend up into the compression zone ofthe slab.

2 shows a modification in which, in sddition to the members ;just described, there provided a series of top ldngitudinal members or rods 5 Secured in or to the rapper angles of the zigzag members 3. This form of reintorcement will take care Be it known that I, ROBERT A. CUM- MINGS, a resident of Beaver, in the county ofBeaver and State of Pennsylvania, have invcnted e 'new and useful Improvement in Reinforced-Cencrete Slebs, ot which the following is e specification.

This invention relates to reinforcement for concrete slabs, such as floor or ceiling constructions for buildings, viaducts and the like, and roots or covers for buildings, vaults, sidewelks and the like.

The object of the invention ,is to provide e reinforcement tor such ccn'crete structures which will teke care of either tension or compression stresses in both surtaces of the shih, end'thereby prevent such slabs from crscking or tailing no matter how supported, whether merely at the ends or edges or at one or any greater number of intermediate points.

In the' Construction ot rei'nforced concrete floors, roots andhll similar structures where the concrete forms zt broad thin body, which can-be termed e slab, itheis been the practice to put the metal reinforcement"practically entirely in one face OI the structure, generally in. or near the lower face, to take care of the tension stresses which exist in .the lower surface of the slab when loaded between the supports. In many such structures the slabs hare crecked on their upper surfaces in members upon which the slab is supported. I have discovered that this failure of the slab as ordinarily constructed is due to'alack of intimate connection of 'the main tension members with the parts in compression and especially at points of contra-flexure in slabs supported as floor sections or the like, in which the main tension members do not always' cross each other perallel with the supports, but are at about 45 degrees'with the supports in order to intersect the diagonal tension Cracks that develop when loaded to destruction.-

The present invention has for its object to overcome this difiiculty and to provide a reinforcement system which absolutely pre ventssuch craclrng and which adapts itself to anysize of slab and entirely irrespective of 'the relative location or number of points` atwhich the slab is supported.

The invention consists, generally stated, in providing a reinforcementfor slabs, preferably in the form of a unit or unitary o f either tension or compression stresses in either the top or bottom surface `equally .well.

Fg. 3 shows the same structure as shown' in Fg. 1 with-the addition of a series of straight transverse members 6 Secured to the longtudnal members 2, and which serve to hold the looped structure of Fig.- 1 from flattening out. V

Figs 4 and 5' show a more' complete form in which the 'longitudinal menbers 2and 5, both at top and bottom are employed' with the zigzag .members 3 united alternatelyto the top and bottom longitudinal members, together with `the straight transverse members 6 at` the bottom and similar-members -7 at the top;- Preferably the straight trans- Verse members 6 and 7 will be of less number'than the zigzag members 3, as shown in Fg. 5. The top member 7 may be placed directly over a-z gzag member,but^- the bot-.

tom members 6 are shown intermediate adjacent zigzag members. This form of reinforce'ment will take care of-either tension or compression stresses in either surface of the slab, and if all the parts ;are of equal strength will take care of these stressesuni- `formly 111 the two surfaces;` It can,'ot

course, be Varied to take care of greater stress one surface than in the other by simply making the top or bottom series of longitudinal members heavier than the other series. j

' V If desired,'the transverse zigzag members may be -arranged as shown in Fig. 6 where each :lternate one of the longitudinal mem- ;bers in the same plane is connected to one jzigzag transverse member, while the remaining longitudinal members in the sape 'plane are connected. to another zgzagmember, as

' will be readily apparent from thedrawings.

In a'll forms of the' reinforcement the several longitudinal and transverse 'members are connected so as 'to form practically a unitay reinforcement structure which can 'be placed in position in the molds or on the centering by unskilled labor and the concrete then filled in, and which will insure the proper distribution of the metal in the concrete.. The connection of the transverse 4 and longitudinal members may be efl'ected in various ways, either by welding at the points where the transverse members cross the longit-udinal members, `or' in some other mechanical" manner suitably securing the parts together; I prefer to make the union by welding, as this can be economically and quickly eifected by the electric welding process and 'ves a firm union. This is shown at 9, Fg. 9, and is the intended manner of' connecting these parts shown in Figs. '1 to 6. Instead of welding, however, the parts 'can be suitably' tied together in any suitable way, or they may be united as shown in Fig. 7 by c'utting' a' tongue lo out Itudinal members are of' materially greater cross-sectional size than the transyerse members. i

To assist in properly positioning the. rein'-,

forcement unit I provide suitable means for pacing saidreinforcement from the center- 1ng. This is shown' in'th`e form of project ing finger's 11 cut from the transverse members and bent outwardly at the lower portion of the reinforcement so as to form supports to rest upon the centering and hold' the reinforcement the proper distance above the latter. f

The form of reinforcement shown in Figs. 1 and 2 may be made by taking metalmesh of any kind of the p'roper size and corrugating the same. The spaces between the longitudinal members may be varied to meet special conditions. Where .the load is rather light these members will be spaced considerable distances apart and the zigzag or looped transverse members will therefore form corresponding large angle's, while where great-er stresses are to be taken care of the longitudinal members will be placed' close together and the transverse zigzag or loped members will have correspondingly smaller angles.

As above stated the members forming the reinforcement are so united as to form prac'- tically a unit which is placed as such before filling in the concrete. This holds the several' members of the reinforcement in theirproper relative positions and insures the proper distribution o'f the metal in the structure and enables the work of putting in place and filling in the concrete to be" performed v by comparatively unskilled labor. With reinforcement: of the character described the slab or floor Construction can be supported in any udesired manner, either at its ends or edges, or at any desired number of points between the ends or edges. In` fact 'the support-s for the slab may be Variously located .since the reinforcement takes care of either compression 'or tension stresses equally well in both surfaces of the slab. The port-ions between thesupports ofcourse are in tension n their lower faces and n compresson n ther upper faces, whle the portons over the supports are in tension in their upper faces and in compression in their lower faces, and there are also points of contraflexure Where the Stress, over the supports merge into those between the supports. The reinforcement described, howeveLefiectually takes' care of all these stresses and therefore the floor or other structure containing the I reinforcement will notcrack by reversals of Stress in adjoning panels over the supports or between the same. i

- What I claim is: v v 1. A reinforcementstructure for concrete slabs comp'rising two series of three or m'ore straight longitudinal bars, the bars of the two serie'slying in different planes With aclear space therebetween, a series of trans- .verse zigzag shaped bars extendin'g at right angles -to the longitudinal bars and lying at 'closeintervals in vertical planes and firmly united at their angles to the two series of.

longitudinal bars, and -a series'of straight transverse bars extendng at right angles to one series of longtudnal bars and firmly united thereto and 'out ot' contact with the other 'series ofstraight bars.

2. A reinforcement structure for concrete slabs comprising two series of three or more straight longituclinal bars, the bars of the two series lying in different planes, a series 'of transverse zigzag shaped bars extending at right angles'to the longituclinal bars and lying at close intervals vertical' planes and tudinal rods lying in angles to the longiand a series of straight transfirmly united at their tudinal bars,

bverse bars arranged at right angles to each series' of, lon gtudinal bars 'and firmly'united thereto, the straight transverse bars of each of the series being out of contact 'With and spac'ecl from other series.

3; Areinforcement structure for concrete slabs comprising a series ofstraight longithe same plane, a series of transverse bars arranged at close ntervals and extending at right angles to the longitudinal rocls and ,intermediate the lat-ter being' formed into loops projecting `towarcl the opposite side of the slab, the 'loopsof any one of said transverse bars lying in a common plane transverse to the longitudinal rods, and a third series of bars extending at right angles to the longitudinal' rods and extending'in a straight line between said rods, both series of transverse bars being 'immotably Secured to the tudinal rods independently of the bars of the other transverse series.

In testimony whereof, I have hereunto set my hand.

ROBERT A. CUMMINGS.

Witnesses:

JOHN SJCORT, -F. W. VVINTER,

the longitudinal bars ot' the' longi- 

